OT: how big would it be? - PCBs at home

From: Richard Erlacher <edick_at_idcomm.com>
Date: Sun Oct 24 19:41:45 1999

First of all, I haven't read ALL of this thread, but I recall Tony or
someone else replying to him saying something about the method for making
plated through two-sided boards in your home. I've never met anyone aside
from professionals with scads of equipment who could do that, but it seems
to me that the method which was described to me was to start with bare
fiberglass/epoxy panels, drill them, then apply a slightly conductive
coating in liquid form which had to be forcibly dried (perhaps baked) before
the resist was applied. The boards were then exposed, the films applied to
registration targets on each side, to a powerful UV light, for which some
prefer to use direct sunlight, and the boards subsequently developed, then
etched.

Has any of you ever encountered an approach to this that could be managed in
the home environment with equipment costing, nominally, less that a k-buck
or two and achieving nominally 10-mil traces with 8-10 mil separation or
anything close to that? How about a dry-film solder mask?

Please share your experience, real or semantic.

Dick

-----Original Message-----
From: Roger Merchberger <zmerch_at_30below.com>
To: Discussion re-collecting of classic computers
<classiccmp_at_u.washington.edu>
Date: Sunday, October 24, 1999 5:21 PM
Subject: Re: OT: how big would it be? - PCBs at home


>On or about 07:15 PM 10/23/99 +0100, Tony Duell was caught in a dark alley
>speaking these words:
>
>>Oh, don't get me started on trying that... And that toner-transfer film
>>isn't that good either...
>
>Isn't that good? My, you're certainly in the mood of understatement today,
>Tony. I've tried that stuff (thinking... This is cool. I can finally
>prototype PCB boards for my classic interfacing projects relatively
>easily...) and I can officially say that it really, really, really sucks.
>And the worst part? It's not that cheap, either.
>
>(certainly affordable, if it worked... which it doesn't.)
>
>For the problems with acetate, try getting a transparency film designed for
>the actual printer that you intend on using. Toners are quite different,
>including their fusing temperatures, fineness, and other factors. Another
>thing to watch for with this iron-on crap (or laser film, or whatever):
>Don't run it thru the printer twice. The high fusing heat changes something
>in the media that seems to make it right close to worthless the 2nd time
>round.
>
>I think that's what happened to me; the 600 DPI HP's use a "micro-toner"
>which fuses at a higher temperature, and I think it changed the media so it
>wouldn't "iron-on" easily, not to mention I don't think the iron got hot
>enough to xfer the toner if that's a factor on the process working right.
>
>Some of the newer "photo" inkjets might work pretty well for artwork,
>too... My wife's Epson Photo 700 does this thing called "micro-weave" for
>the photo papers. It essentially takes 1/4 swipes at the image, and prints
>the image 4 times at 1/4 density with the full printhead, so there's
>virtually no banding. I've not tried it (have a laser) but it just might
work.
>
>As always, YMMV and all that...
>Roger "Merch" Merchberger
>=====
>Roger "Merch" Merchberger -- zmerch_at_30below.com
>SysAdmin - Iceberg Computers
>===== Merch's Wild Wisdom of the Moment: =====
>Sometimes you know, you just don't know sometimes, you know?
Received on Sun Oct 24 1999 - 19:41:45 BST